Still seems a bit high compared to what everyone else is posting here... could it be the market is driving the higher money factor because of my area? (Washington D.C. metropolitan)

They're trying to pull a maneuver.--- They shouldn't be adding sales tax on top of the $104,175. Sales tax is paid on the lease payment and/or any cap cost reduction. Did they give you this in the contract, or over email?

I would guess that when they paper this deal (which you absolutely shouldn't do) they would show your purchase price as $110,400 and that 6K tax line would be much smaller, reflecting the 6% of the net caps you have listed -$2,200 and $750.